1. Field of the Invention
The present invention generally relates to joints and connecting devices used for the joints, and more particularly, to a rotatable joint and a connecting device used for the rotatable joint.
2. Discussion of the Related Art
Rotatable joints afford movement for arms of mechanical devices. As such, a mechanical device, having an arm designed for movement, includes a rotatable joint. The rotatable joint may join an arm or an actuating portion to a supporting portion (generally the body) of the mechanical device. In other words, the actuating portion is attached to the supporting portion by the rotatable joint. A typical actuating portion includes a base fixed to the supporting portion, a movable member fixed to the actuating portion, and a pivot shaft for connecting the base and the movable member. A pivot hole is defined in the base, and one end of the pivot shaft rotatably engages in the pivot hole. The other end of the pivot shaft is rotatably connected to the movable member by a pin. Thus, the movable member not only can rotate together with the pivot shaft relative to the base, but can also rotate relative to the pivot shaft.
Due to friction, wear and tear of usage, the pivot shaft and the pin of the rotatable joint may become worn out, thus the rotatable joint may become unstable and control of the actuating portion may suffer.
Therefore, a new rotatable joint that is less likely to be worn out, and to be stable over the long term, is desired.